POS0911 ULTRASOUND-DETECTED SYNOVITIS AMONG INDIVIDUALS AT RISK OF RHEUMATOID ARTHRITIS INCREASES THE RISK OF DEVELOPING CLINICAL ARTHRITIS IN THE FUTURE
Authors: P. Hanova, K. Prajzlerová, N. Petrovská, M. Gregová, H. Mann, K. Pavelka, J. Vencovský, L. Šenolt, M. Filková
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> During the transition to rheumatoid arthritis (RA) patients pass through several phases. In the preclinical phase, the presence of anti-citrullinated protein antibodies (ACPA) can be detected [1]. A set of clinical characteristics for patients with arthralgia who are at risk of progression to RA was established (clinically suspected arthralgia; CSA) [2]. Ultrasound (US) is more sensitive diagnostic tool in detecting synovitis than clinical assessment and was recommended to use in diagnostics of RA. <h3>Objectives</h3> To test if ultrasound-detected synovitis among patients at risk of progression to RA increases the risk of developing clinical arthritis (CA) in the future. <h3>Methods</h3> ACPA+ individuals with arthralgia and/or those fulfilling CSA criteria were enrolled into the study and were assessed in 3 months interval (routine clinical investigation with laboratory tests, 68-joint count, US assessment). Tender and swollen joint counts were provided by an independent investigator. Sonographer was blinded to all clinical and laboratory data. CA was defined as clinically swollen and tender joint. All US assessments were provided by a single experienced investigator. Thirty joints US score was assessed bilaterally in wrist, MCP I-V, PIP II-V (dorsal and palmar approach), MTP II-V (dorsal approach), ankle (dorsal, medial and lateral approach). US synovitis was defined according the EULAR-OMERACT and scored separately in grey-scale (GS; 0-3) and Power Doppler (PD; 0-3), and combined GS+PD score GLOESS (Global OMERACT-EULAR Score System) was used. For the statistical analysis, we used GraphPad Prism 8.0.0 software (Wilcoxon-Mann-Whitney test), and relative risk ratio (RR). <h3>Results</h3> 159 patients were enrolled into the study (93% female). 95 individuals were ACPA+ (38% fulfilled the CSA criteria additionally), 64 individuals fulfilled the CSA criteria and were ACPA-. At baseline, GS≥1 was detected in 109 patients (67%), PD≥1 was found in 30 individuals (19 %). Single erosion was found by US only in 4 patients (3%) at baseline. 33 patients (21%) developed CA during follow up (mean 13 months after enrolment into the study). No statistical difference in US synovitis score was found between ACPA+ vs. ACPA- and CSA+ vs. CSA- groups at baseline. RR to develop CA at the patient level in patients with GS≥2 at baseline was 1.58 (95% CI 1.16- 2.18; p&lt;0.01), in PD≥1 the RR was 3,14 (95% CI 1.74-5,7; p&lt;0.001), in PD≥2 RR was 7,64 (95% CI 3,1-18,82; p&lt;0.0001). GLOESS score&gt;5 showed RR 3,82 (95% CI 1,74-8,4; p&lt;0,001). US-detected synovitis preceded clinical finding of arthritis by 3 months (SD 1,2). <h3>Conclusion</h3> US-detected synovitis in patients at risk of RA further increases the risk of developing clinical arthritis in a larger prospective study. US detected synovitis in joints appears about 3 months prior synovitis detected by routine clinical assessment. <h3>References</h3> [1]Bos, W. H., Wolbink, G. J., Boers, et al. Arthritis development in patients with arthralgia is strongly associated with anti- citrullinated protein antibody status: a prospective cohort study. Annals of the Rheumatic Diseases, 2010;69(3):490-4. [2]van Steenbergen HW, Aletaha D, Beaart-van de Voorde LJJ, et al. EULAR definition of arthralgia suspicious for progression to rheumatoid arthritis. Annals of the Rheumatic Diseases 2017;76:491-6. <h3>Acknowledgements</h3> Project NU22-05-00226. <h3>Disclosure of Interests</h3> None Declared.